Skin is subject to abuse by many extrinsic (environmental) factors as well as intrinsic (chronoaging) factors. A common extrinsic factor is exposure to ultraviolet radiation. Whether extrinsic or intrinsic, the abuse results in wrinkling of the skin. To many people, skin wrinkles are a reminder of the disappearance of youth. As a result, the elimination of wrinkles has become a booming business in youth-conscious societies. Treatments range from cosmetic creams and moisturizers to various forms of cosmetic surgery.
Chronoaging results in the thinning and general degradation of skin. As the skin naturally ages, there is a reduction in the cells and blood vessels that supply the skin. There is also a flattening of the dermal-epidermal junction which results in weaker mechanical resistance of this junction. As a consequence, older persons are more susceptive to blister formation in cases of mechanical trauma or disease processes. (See Oikarinen, (1990) "The Aging of Skin: Chronoaging Versus Photoaging", Photodermatal. Photoimmunol. Photomed., Vol. 7, pp 3-4).
N-acetyl-L-cysteine, a preferred active of the present invention, has been used as a mucolytic, corneal vulnerary and an antidote to acetaminophen poisoning (The Merck Index, (1989) 11th Edition, p.14). European Patent Application 219 455, Fabbro, published Apr. 22, 1987, discloses a dermatological and skin cosmetic, topical, pharmaceutical composition containing N-acetyl-L-cysteine as the active constituent. The composition is disclosed as being useful for the prevention and treatment of sunburn and for increasing the speed of skin pigmentation bronzing.